喀斯特小流域不同土地利用方式土壤物理性状分析

以广西都安澄江喀斯特小流域为研究单元,分析了流域不同土地利用方式下土壤主要物理性质的变化。结果表明:随着自然林地向灌丛地、灌草丛地、草地、人工林地、梯化旱地、旱地、坡耕地转变,土壤容重、pH呈增加趋势,而土壤含水量、土壤总孔隙度、电导率逐渐降低。土壤电导率对不同土地利用方式的响应程度最强烈,土壤容重、含水量和总孔隙度的响应程度居中,pH最小。在不同土地利用方式下,土壤总孔隙度、含水量、电导率及pH的变化均与土壤容重的变化有关。随着土壤容重的增加,总孔隙度和含水量均减少,电导率降低,而pH升高。综合分析土壤物理性质各项主要指标,发现自然林地土壤物理性质最优,灌丛地、灌草丛地、草地、人工林地、退耕地的土壤物理性质次之,梯化旱地、旱地、坡耕地最差。

Analysis on Physical Features of Karst Small Watershed Soil under Different Land Uses

With the karst small watershed of Chengjiang in Du′an County as the research unit,the changes in the physical properties of soil under different land use patterns were analyzed.As indicated by the results,soil bulk density and pH are increasing while the soil water content,the total porosity and electrical conductivity of soil are gradually reducing along with the natural woodland converting to shrub land,irrigation of bushes and grass,artificial forest,ladder dry lands,dry land,sloping cultivated land.Electrical conductivity responds the strongest under different land uses,while the level of response for soil bulk density,water content and total porosity are moderate,while that of pH is minimal.Under different land uses,the changes of soil porosity,water content,electrical conductivity and pH are related to the changes of soil bulk density,with the increase of soil bulk density,total porosity and water content all reduce,the conductivity reduces,too,but the pH increases.Comprehensive analysis of main indicators of soil physical properties found that the soil physical quality of natural woodland is optimal,that of shrub land,irrigated grass,lawn,artificial soil and return cultivated land are in the second grade,and that of ladder dry land,dry land and sloping farmland are the lowest.